Hugo O'Donnell y Duque de Estrada, 7th Duke of Tetuan, GE, OM (born 29 September 1948), is a Spanish peer and historian who was the vice president of the International Commission for Maritime History, censor of the Real Academia de la Historia and elect member of the Royal Historical Society.
He succeeded his father, Leopoldo O'Donnell y Lara, as Duke of Tetuan and Grandee of Spain (confirmed by Ministry of Justice in Madrid: BOE 240 dated 7 October 2005). The title commemorates the conquest of Tetuan in Morocco in the mid-19th century by his ancestor, Leopoldo O'Donnell y Jorris, 1st Duke of Tetuan and Prime Minister of Spain.
He is the recognised Tánaiste (heir apparent) to The O'Donnell of Tyrconnell, Prince and Chief of the Name of the O'Donnells, who is a retired Franciscan priest, Fr. Hugh O'Donel, and whom he will succeed as Chief of the Name, according to the books by authors Berresford Ellis and Curley referenced below.
The duke is an active member of the Clan Association of the O'Donnells of Tyrconnell (of Ireland), and he is a Knight of Malta. The duke is a naval historian, and also a former naval commander and Minister for the Marine in Spain.
The duke is married to Maria de la Asunción Armada y Díez de Rivera. Together, they had four children: